Monitoring of the transesterification reaction by continuous off-line density measurements

Abstract

The main route for industrial production of biodiesel is through the transesterification reaction of different source of triglycerides. Continuous monitoring of the process is very important in order to optimize operational parameters, foresee troubles and guarantee the quality of final product. In this work, the transesterification of cottonseed oil at 50 °C and 70 °C, with methanol/oil molar ratios of 4.5, 6.0 and 7.5 was carried out, and the oil conversion as a function of reaction time was evaluated by 1H NMR. The density of the reaction mixture, at these experimental conditions, was measured as a function of the reaction time by an off-line methodology. From the density-time and oil conversion-time profiles an operative relationship between conversion, density, alcohol to oil ratio and temperature was established.